1. Field of the Invention
The invention a relates to the field of lighting and/or light indicators, notably for a motor vehicle. More particularly, the invention relates to the cooling of light modules of a motor vehicle headlamp.
2. Description of the Related Art
The light sources present in the headlamps and lighting devices are subject to overheating and often need to be cooled. This is particularly the case for semiconductor light sources, such as light-emitting diodes or laser diodes. These light sources are indeed very small in size while offering significant lighting power. They are usually disposed on a printed circuit type board and are often thermally coupled to one or more radiators.
The published patent document DE 10 2007 043 961 A1 discloses a headlamp comprising a plurality of light modules whose light sources of the semiconductor type are coupled to radiators. These radiators are cooled by a stream of air forced through a duct. This duct comprises a cooling air inlet set into motion by a fan, a plurality of outlets opening near coolers and an air passage connecting the inlet to the outlets. The passage comprises branches dividing the air flow of the inlet into several flows toward the various outlets. The construction of the duct is conventional in that it is the branches of the duct that distribute the inlet air flow. The number of possible outlets is limited, however, by the branches and, also, by the distribution of the specific flows from the various outputs is not controlled. An unidentified pressure loss downstream in one of the branches can have a significant adverse effect on flow distribution. Furthermore, the creation of branches is not without certain congestion and production cost problems.
Similarly to the previous document, patent document FR 2 946 730 A1 discloses a motor vehicle headlamp, comprising a plurality of modules whose light sources are cooled by a flow of cooling air circulating through a duct disposed between a fan and respective radiators of the light sources. Similarly to the duct of the previous teaching, the duct is bulky and complex in shape from a production cost point of view. The flow distribution presents the same drawbacks as in the previous teaching.
Patent document US 2011/0051453 A1, now issued as U.S. Pat. No. 8,337,063, discloses a motor vehicle headlamp, including several light modules whose light sources are in thermal contact with a common radiator. A fan is disposed in the low position and at a distance from the radiator to allow the light sources and the radiator to pivot in relation to a directional lighting function. This solution is interesting in its simplicity but has constraints regarding the location of the modules and more particularly the light sources.